The world's first commercially available PCWhen Micro Instrumentation and Telemetry Systems launched the Altair 8800 in 1975, it hoped to sell as many as 200 of the new machines to the public. Instead, thousands of orders poured in to the small Albuquerque, NM, firm. The Altair was a "hobbyist" computer because customers had to construct the machine from a kit. The designation "8800" referred to the fact that the computer used the new Intel 8080 chip. As sold, the Altair was programmed in direct binary code, using the toggle switches on the front panel to enter one's and zero's. Input and output were only visible with the small flashing lights on the front panel. However, knowledgeable owners could use expansion slots in the machine to add boards linked to a keyboard or monitor. Soon after the computer was on the market, Bill Gates and Paul Allen wrote a BASIC (Beginners' All-purpose Symbolic Instruction Code) interpreter for the machine, making it possible to program it much more easily. This product helped them create their software company, Microsoft Corporation.